I have recently tried to an indexed png image in scikit-image, but didn't find a way to
make it using skimage.io imread.
Basically if a png file is an indexed array, in matlab you can load it as two separate arrays. One of them
will be a one dimensional array and another one will represent a look up table which will map
each index to a unique color.
In matlab it can be done using:
[im, colormap] = imread('indexed.png');
Using PIL library:
from PIL import Image
import numpy as np
im = Image.open("image.png") # Replace with your image name here
indexed = np.array(im)
There is more about this problem here:
Is it possible to do the same but using skimage.io imread and plugin argument, assuming
that I have PIL installed?